Mars has long been heralded as the next planet Earthlings can escape to when this planet becomes uninhabitable, just a redder, colder, and darker version.
But some are wondering if we shouldn't pay attention to Earth's other red—though warmer—neighbor: Venus.
It's a serious thought that is getting some serious backing in the space research community. NASA recently announced it has hatched a scheme for rocketing giant airships to Venus—and sending astronauts to live aboard the airships for up to a month at time for research purposes. A possible manned Venus mission could boost NASA’s efforts to push the boundaries of human space exploration to farther—and frankly, weirder—planets.
The airship is part of the High Altitude Venus Operational Concept, or HAVOC. Basically, it involves a rocket, fired from Earth, boosting a deflated blimp to Venus’s atmosphere, where the airship would automatically inflate. Additional rockets would transport the human explorers to the waiting light-than-air vessel.
The plan might seem fantastical, but for NASA the hardware is straightforward. Still, experts told The Daily Beast that, while not unrealistic on a technological level, HAVOC is unlikely to launch any time soon.
HAVOC is the brainchild of the Space Mission Analysis Branch at NASA's Langley Research Center in Virginia. With its extraterrestrial airship concept, the branch aims to solve a big problem with Venus exploration, namely, its toxic carbon dioxide atmosphere and sulfuric acid clouds. These clouds could be toxic to humans should they ever land on the planet.
"The atmosphere traps the small amount of energy from the sun that reaches the surface along with the heat the planet itself releases," the Space Mission Analysis Branch explained on its official website. "This greenhouse effect has made the surface and lower atmosphere of Venus one of the hottest places in the solar system."
HAVOC would be an expensive distraction from the space agency's more urgent priorities such as returning to the moon and sending astronauts to Mars, experts told The Daily Beast. And besides, there are easier ways to explore Venus than deploying manned blimps. The Soviet space agency proved that with a robotic mission back in the 1980s.
HAVOC "is an off-the-mainstream study with essentially no chance of being implemented in the foreseeable future," John Logsdon, founder of the Space Policy Institute at George Washington University, told The Daily Beast.
So Venus’s atmosphere means that landing astronauts on the surface of Venus is out of the question. But in contrast to its roiling surface, Venus' upper atmosphere—beginning at an altitude of around 30 miles from the surface, is "benign," according to the Space Mission Analysis Branch.
A lighter-than-air vehicle floating above the sulfur clouds "could carry either a host of instruments and probes, or a habitat and ascent vehicle for a crew of two astronauts to explore Venus for up to a month," the Space Mission Analysis Branch explains.
Why are scientists so gung-ho about exploring the second rock from the sun and not the Red Planet? Well, there's a lot astronauts could learn from Venus's unique atmosphere about our own planet. "A thorough sampling schedule might be able to reveal the natural history of Venus and how the current greenhouse conditions came to be," Dirk Schulze-Makuch, a professor at the Center for Astronomy and Astrophysics at the Technical University Berlin, told The Daily Beast. "This would provide needed insights also for our planet and greenhouse warming."
Schulze-Makuch said a Venus mission might also be able to detect evidence of past volcanic activity on Venus, a key finding for understanding the planet’s development.
Balloon-based Venus exploration is hardly science fiction. In 1985, the Soviets deployed the Vega 2 probe to the second planet from the sun. The probe included a sensor-carrying balloon that floated some 30 miles over Venus's surface, traveling nearly 7,000 miles over the course of several days before NASA lost contact with it.
Vega 2 "worked pretty well," James Oberg, a former NASA mission controller, told The Daily Beast. A bigger, manned balloon "is a big step, especially with the need for a round-trip ticket," Oberg added. But advances in artificial intelligence, robotics, and remote operation mean a HAVOC-style vehicle soon could be possible.
The problem is not the technology. It's paying for it—especially when NASA has much higher priorities. The space agency is working hard to develop a new manned capsule and a super-heavy rocket to carry it by 2019, while also setting up mining operations on the moon in order to establish bases that could support a manned Mars mission as early as the 2030s.
NASA hasn't formally calculated the overall cost of the Mars effort, but O. Glenn Smith, a former manager of shuttle systems engineering at NASA’s Johnson Space Center, calculated that the first Mars mission alone could set back taxpayers $230 billion.
NASA's annual budget has averaged $18 billion in recent years, and it seems unlikely the space agency will enjoy big budget boosts any time soon. Indeed, the Trump administration has proposed auctioning off the International Space Station to private operators as a cost-saving measure—a move many lawmakers oppose.
Despite The Daily Beast's repeated efforts to arrange interviews, NASA declined to comment for this story.
Maybe NASA can keep the space station, get back to the moon and then continue on to Mars. But can it afford to also send balloons to Venus? “The science harvest would have to be substantial to justify the costs of such a mission,” Schulze-Makuch warned.
For most of the experts The Daily Beast spoke to, Venus is interesting but not a high priority when new missions to the moon and Mars are much farther along. "It's something we might want to do some day, but it's not the logical next step," David Grinspoon, an astrobiologist with the nonprofit Planetary Science Institute, told The Daily Beast.
The case for a manned blimp mission to Venus got a lot trickier in early June, when NASA announced it had discovered on Mars evidence of organic carbon, a basic building-block of life.
Venus-supporters are probably aware they're second in the popularity contest, but they aren't giving up without a fight. "The recent findings of many organics on Mars don´t help" HAVOC's chances, Schulze-Makuch said. "The spotlight [is] again back on Mars."
If NASA wants to explore Venus without abandoning its other high-profile missions, it might want to think smaller than a giant, manned balloon. "There are probes you could send that are orders of magnitude less cost," Grinspoon said. "Send machines."